Collaborative Research: Trade Liberalization in a World of Heterogenerous Firms: Theoretical and Quantitative Results

异质企业世界中的贸易自由化：理论和定量结果知识价值用于预测北美自由贸易协定对贸易流动影响的应用一般均衡模型未能捕捉到随后发生的贸易爆炸以及随之而来的跨工业部门贸易再分配。对加拿大、墨西哥和美国之间贸易流动的分类分析表明，贸易增长的很大一部分是以前没有出口或出口很少的货物的贸易，即所谓的广泛贸易差额。这一建议表明，机械地将这一见解纳入北美贸易模式的粗略预测中，对北美自由贸易协定颁布后的贸易模式的预测要比多部门应用通用电气模型的预测好得多。数据表明，捕捉贸易的广泛边际对于理解贸易政策的影响很重要，这意味着需要产生广泛边际增长的模型。拟议的研究将利用企业层面贸易理论的进展来建立适合于政策分析的模型。该项目的最初目的是评估基于两种类型的产业结构的模型的属性：具有进入成本的垄断竞争，如Melitz（2003）和完全竞争，如Eaton和Kortum（2002）。构建足够灵活的模型以进行政策分析，需要对标准理论进行概括。在Kehoe和Ruhl （2009b）的基础上，模型被扩展到包括企业异质性和潜在生产力的广义分布的多个维度。开发了一个映射方案，将模型中的公司级决策与数据中的产品级和行业级聚合相匹配。更广泛的影响为了了解自由贸易和保护主义的政策辩论，经济学家需要更好地了解贸易对不同行业的影响。本文提出的研究开发了一些模型，将当前研究中流行的企业层面的贸易模型转化为对政策分析有用的模型。从方法上讲，这类模型将使经济学家能够分析政策对产业结构的影响。目前，美国正在与几个拉丁美洲国家谈判自由贸易协定，与韩国的自由贸易协定等待各国立法机构的批准。成功的贸易谈判需要仔细评估贸易政策对个别工业部门的影响。没有对贸易政策的分配影响的准确理解，就很难向决策者提出建议，也很难向公众介绍这种自由化政策的优点

Trade Liberalization in a World of Heterogeneous Firms: Theoretical and Quantitative ResultsIntellectual MeritThe applied general equilibrium models used to predict the impact of the North American Free Trade Agreement on trade flows failed to capture the explosion of trade that occurred subsequently and the accompanying redistribution of trade across industrial sectors. The analysis of disaggregated trade flows between Canada, Mexico, and the United States shows that much of the increase in trade has been trade in goods not previously exported or exported very little - what is known as the extensive margin of trade. This proposal shows that mechanically incorporating this insight into crude projections of North American trade patterns would have produced significantly better predictions of the pattern of trade following the enactment of NAFTA than did multisectoral applied GE models. The data suggest that capturing the extensive margin of trade is important for understanding the impacts of trade policy, which implies that models that generate extensive margin growth are needed. The proposed research will use advances in the firm-level theory of trade to build models that are suitable for policy analysis. The initial aim of the project is to evaluate the properties of models based on two types of industrial structures: monopolistic competition with entry costs, as in Melitz (2003) and perfect competition, as in Eaton and Kortum (2002). Constructing models flexible enough to be estimated for policy analysis requires generalizing the standard theories. Based on Kehoe and Ruhl (2009b), the models are extended to include multiple dimensions of firm heterogeneity and generalized distributions over underlying productivity. A mapping scheme is developed to match the firm-level decisions in the model to the product-level and industry-level aggregates in the data.Broader ImpactTo inform the policy debate over free trade and protectionism, economists need to better understand the impact of trade on different industries. The proposed research develops models that transform the firm-level trade models popular in current research into models useful for policy analysis. Methodologically, these sorts of models will allow economists to analyze the impact of policy on the structures of industries. Currently, the United States is negotiating free trade agreements with several Latin American countries, and a free trade agreement with South Korea waits to be approved by the legislatures in each country. Successful trade negotiations require careful evaluation of the impact of trade policy on individual industrial sectors. Without an accurate understanding of the distributional impacts of trade policy, it is difficult to advise policy makers and to inform the public on the merits of such liberalization policies